Find the latest SCN # in phisical standby

I have set up a real time apply physical standby and trying to find how Real Time it is. However it seems that it is hard to find the latest SCN# on physical standby database, v$database (current_scn) only gets updated to the last scn which has been archived. Here is what I got:  

SQL> select recovery_mode from v$archive_dest_status where dest_id=2;

RECOVERY_MODE

MANAGED REAL TIME APPLY   SQL> select name, value, time_computed from v$dataguard_stats where name='apply lag';

NAME            VALUE                TIME_COMPUTED



--------------- -------------------- ------------------------------


apply lag       +00 00:00:00         12-JAN-2010 15:26:02

 

 

Primary last change time:  

SQL> select scn_to_timestamp(current_scn) from v$database;

SCN_TO_TIMESTAMP(CURRENT_SCN)

12-JAN-10 03.05.41.000000000 PM     Standby last change time: - not updated after last log archived  

SQL> select current_scn from v$database;

CURRENT_SCN

  579664324

SQL> select scn_to_timestamp(579664324) from v$database;

SCN_TO_TIMESTAMP(579664324)

11-JAN-10 11.27.27.000000000 PM   SQL> select max(FIRST_CHANGE#),max(NEXT_CHANGE#) from v$archived_log;

MAX(FIRST_CHANGE#) MAX(NEXT_CHANGE#)

• -----------------

         579266831 579664325  

Could someone share some light on this?  

Thanks,

Lu

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